The function and underlying mechanism of TET1 in myelodysplastic syndromes

TET1在骨髓增生异常综合征中的功能及机制

• 批准号: 9914855
• 负责人: Jianjun Chen
• 金额: $ 56.49万
• 依托单位: BECKMAN RESEARCH INSTITUTE/CITY OF HOPE
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-10 至 2023-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9914855
• 关键词: Acute Myelocytic Leukemia; Address; Anemia; Animal Genetics; Animal Model; Attenuated; Basic Science; Blood Cells; Bone Marrow Transplantation; Cell Differentiation process; Cells; ChIP-seq; Chromosome abnormality; Clonal Hematopoietic Stem Cell; Control Groups; DNA; DNA Methylation; Data; Data Set; Development; Dioxygenases; Disease; Down-Regulation; Dysmyelopoietic Syndromes; EZH2 gene; Epigenetic Process; FLT3 gene; Family; Future; Gene Expression Profiling; Gene Mutation; Genes; Goals; Hematopoiesis; Hematopoietic; Hematopoietic stem cells; Histones; Human; In Vitro; Knock-out; Lead; Leukopenia; MLL gene; Maintenance; Malignant - descriptor; Malignant Neoplasms; Modeling; Modification; Molecular; Mus; Mutate; Mutation; Myelogenous; Myeloproliferative disease; NPM1 gene; Oncogenic; Pathogenesis; Pathologic; Patients; Phenotype; Play; Protein translocation; Reporting; Research Design; Risk; Role; Sampling; Signal Pathway; Signal Transduction; Solid; Thrombocytopenia; Translational Research; Transplant Recipients; Tumor Suppressor Genes; Tumor Suppressor Proteins; Validation; Work; Xenograft procedure; cohort; cytopenia; demethylation; gain of function; gene translocation; genome-wide; granulocyte-monocyte progenitors; hematopoietic differentiation; high risk; in vivo; insight; knock-down; loss of function; loss of function mutation; member; mutant; new therapeutic target; novel; overexpression; peripheral blood; progenitor; success; t(8; 21)(q22; q22); transcriptome sequencing; transplant model; whole genome

PROJECT SUMMARY (ABSTRACT): Title: The function and underlying mechanism of TET1 in myelodysplastic syndromes. Background: Myelodysplastic syndromes (MDS) is a heterogenous group of clonal hematopoietic stem cell disorders, characterized by peripheral blood (PB) cytopenias (e.g., anemia, leukopenia, and thrombocytopenia). Although chromosomal abnormalities, gene mutations and some histone/DNA epigenetic changes have been reported in MDS, the molecular mechanisms underlying the pathogenesis of MDS have not been well understood. TET1, the founding member of the TET methylcytosine dioxygenase family, was first identified as a fusion partner of the MLL gene in acute myeloid leukemia (AML). In contrast to the previous thought that all three TET genes (TET1/2/3) may function as tumor suppressor genes in cancers, our recent work showed that TET1 is overexpressed in certain subtypes of AMLs, and plays a critical oncogenic role in the development of such AMLs. However, the role of TET1 in MDS remains unknown. Recently, in analysis of a genome-wide gene expression profiling dataset of a large cohort of human primary MDS patients, we found that TET1 is also aberrantly overexpressed in all the major subtypes of MDS analyzed, which was confirmed by qPCR in our in-house MDS samples. Tet1 is also overexpressed in various murine MDS models. We then showed that knockdown of TET1 expression substantially promoted differentiation of MDS cells, and forced expression of wild-type TET1 (but not catalytic inactive TET1 mutant) caused the opposite phenomenon. TET1 depletion also significantly inhibited MDS progression and diminished cytopenias in vivo. Furthermore, we have identified a set of potential/candidate target genes of TET1 in MDS, and some of them have been implicated in the pathogenesis of MDS. Objective/Hypothesis: TET1 plays an essential role in MDS pathogenesis through epigenetically regulating expression of a set of essential target genes. Specific Aims: (1) To determine whether TET1 is required for the development and maintenance of MDS; (2) To determine whether forced expression of TET1 can promote MDS development and progression, and whether TET1 function is dependent on its catalytic activity; and (3) To decipher the molecular mechanism(s) underlying the pathological role of TET1 in MDS. Study Design: 1) We will conduct loss-of-function studies in genetic animal MDS models and patient-derived xeno-transplantation (PDX) MDS models to determine whether Tet1/TET1 expression/function is required for both development and maintenance of MDS (Aim 1). 2) We will conduct gain-of-function studies with the above MDS models to determine whether forced expression of Tet1/TET1 can promote MDS development and progression via a catalytic activity-dependent mechanism (Aim 2). 3) We will perform genome-wide ChIP-seq, 5hmC-seq, and RNA-seq to identify all direct targets of TET1 in MDS, followed by the validation/functional studies of a set of top targets of TET1 in vitro and in vivo, to elucidate the molecular mechanism underlying TET1’s role (Aim 3).

项目摘要（摘要）： 标题：TET1在骨髓增生综合征中的功能和基础机制。 背景：骨髓增生综合征（MDS）是一组异质的克隆造血干细胞 疾病，其特征是周围血（PB）细胞质（例如贫血，白细胞减少和血小板减少症）。 尽管已经报道了染色体异常，基因突变和一些Hisstone/DNA表观遗传学变化 在MDS中，尚未很好地理解MDS发生的基础的分子机制。 tet1， TET甲基霉素二氧酶家族的创始成员首先被确定为融合伙伴 急性髓样白血病（AML）中的MLL基因。与以前的三个TET基因相比 （TET1/2/3）可能在癌症中起抑制肿瘤基因的作用，我们最近的工作表明Tet1是 在AML的某些亚型中过表达，并且在此类AML的发展中起着关键的致癌作用。 但是，TET1在MDS中的作用仍然未知。最近，在分析全基因组基因表达时 分析了大量人类主要MDS患者的数据集，我们发现TET1也异常 在分析的所有主要子类型中过表达，这是qPCR在我们内部MDS中证实的 样品。 TET1在各种鼠MDS模型中也过表达。然后，我们证明了Tet1的敲除 表达基本上促进了MDS细胞的分化，并强迫表达野生型TET1（但不是 催化无活跃的TET1突变体）引起了相反的现象。 TET1耗竭也显着抑制 MDS的进展和体内细胞质减少。此外，我们已经确定了一组潜在/候选者 MDS中TET1的靶基因，其中一些在MD的发病机理中暗示。 客观/假设：TET1通过表观遗传调节在MDS发病机理中起着至关重要的作用 表达一组基本靶基因。 具体目的：（1）确定MDS开发和维护是否需要TET1； （2）确定强迫表达TET1是否可以促进MDS的发展和进展，并且 TET1功能是否取决于其催化活性； （3）破译分子机制 TET1在MDS中的病理作用的基础。 研究设计：1）我们将在遗传动物MDS模型和患者衍生的遗传动物MDS模型中进行功能丧失研究 异种移植（PDX）MDS模型，以确定是否需要TET1/TET1表达/函数 MDS的开发和维护（AIM 1）。 2）我们将使用上述MDS进行功能收益研究 确定TET1/TET1强制表达的模型是否可以促进MDS的发展和进展 通过催化活性依赖性机制（AIM 2）。 3）我们将执行全基因组CHIP-SEQ，5HMC-SEQ， 和RNA-Seq确定MDS中TET1的所有直接靶标，然后进行验证/功能研究 TET1在体外和体内的最高靶标，以阐明TET1作用的分子机制（AIM 3）。